VHS Capture - Advice needed on DV

[nharikrishna]

I have about 10 VHS Cassettes to be converted to DVDs, and I will be getting more VHS to convert through friends, families, neighbors & co-workers. I do it for a charge for them.

I have a very good S-VHS VCR (JVC HR-S7600AM) with built-in digital TBC & 3D Noise Reduction. Works very well. I also have a Canopus ADVC 110 for Analog-to-Digial capture, which also workes very well. I use S-Video connection from VCR to Canopus for capture.

The Canopus ADVC 110 captures the Analog into Consumer DV format only, which outputs the stream to the Computer via Firewire.

Now my question is, is this set-up sufficient for professional VHS to DVD conversion? I am particularly interested to know, if there is a better method of capturing VHS to computer, other than converting it to Consumer DV format? some kind of raw video which is superior to DV? Am I losing any kind of quality by capturing in DV format?

I use the built-in MainConcept encoder in Premiere Pro for transcoding the DV captured AVI file to MPEG-2.

Thanks for the help.

[zoobie]

you can cap lossless but at the end of the day, you'll still need to conform to the DVD spec
most simply cap DV because it's such a good format and go from there

[nharikrishna]

you can cap lossless but at the end of the day, you'll still need to conform to the DVD spec
most simply cap DV because it's such a good format and go from there

Thanks, so you mean to say lossless for VHS is "not needed" or going DV is "good enough" & "convenient" than going lossless?

[edDV]

you can cap lossless but at the end of the day, you'll still need to conform to the DVD spec
most simply cap DV because it's such a good format and go from there

Thanks, so you mean to say lossless for VHS is "not needed" or going DV is "good enough" & "convenient" than going lossless?

I think "good enough" & "convenient" says it correctly. The DV encode is done in hardware and the files are reasonable in size.

Full uncompressed capture is the "pro" route but you risk frame loss without a RAID and the files are huge.

A geek hobbyist alternate would be capture through a Huffyuv software codec that "losslessly" reduces capture bit rate to a single drive sustained rate. Vegas will decode Huffyuv using the "Video for Windows" AVI timeline. Timeline responsiveness depends on CPU power.

For VHS, I say test the different methods for representative clips then make up your mind.

[nharikrishna]

Thanks again edDV...but since I am using Canopus ADVC 100 which outputs only in DV format through Firewire, I have no chance of using Huffyuv???

[bendixG15]

You may find interest in this recent discussion about the Canopus box and its "goods and bads" for "professional" results.

https://forum.videohelp.com/threads/313473-NOTE-A-Canopus-DV-box-does-not-replace-a-TBC!

[vectorthom]

Full uncompressed capture is the "pro" route but you risk frame loss without a RAID

How does capturing to a RAID vs. a standard HDD help prevent frame loss?

[edDV]

Full uncompressed capture is the "pro" route but you risk frame loss without a RAID

How does capturing to a RAID vs. a standard HDD help prevent frame loss?

A single hard disk has a maximum sustained data rate. If the capture data coming in exceeds this rate, the buffer fills causing frame loss. Or if another app calls the disk, the buffer can fill and there is frame loss. Or if the drive is fragmented, disk seeks can cause frame loss.

First consideration for uncompressed capture is an isolated second drive (separate from the OS drive) on a separate disc controller on the PCI bus. A desktop computer will allow PCI bus mastering for complete capture disc isolation.

This may still result in frame loss because hard disks vary in sustained data rate from the inside tracks to the outside tracks.

Second consideration is RAID zero which combines two or more drives for double or more the sustained capture rate. A Two disk RAID also averages sustained rate for the full recording length.

[edDV]

Thanks again edDV...but since I am using Canopus ADVC 100 which outputs only in DV format through Firewire, I have no chance of using Huffyuv???

The ADVC encodes to DV format which is ~28 Mb/s data rate. No Huffy needed for this low rate.

Huffyyuv is intended to slow an uncompressed capture using the CPU to compress. The data rate is slowed to prevent frame loss to a single capture drive.

Uncompressed data rates:

SMPTE-259M 10 bit (SDI) = 270 Mb/s (~250 Mb/s for video stream)
Square pixel 768x486 = 146 Mb/s + audiio
Rec 601 8 bit 704x480 ~= 166 Mb/s

Huffyuv codec reduces these ~ 1/2.7 or 0.37x

[nharikrishna]

Thanks again edDV...but since I am using Canopus ADVC 100 which outputs only in DV format through Firewire, I have no chance of using Huffyuv???

The ADVC encodes to DV format which is ~28 Mb/s data rate. No Huffy needed for this low rate.

Huffyyuv is intended to slow an uncompressed capture using the CPU to compress. The data rate is slowed to prevent frame loss to a single capture drive.

Uncompressed data rates:

SMPTE-259M 10 bit (SDI) = 270 Mb/s (~250 Mb/s for video stream)
Square pixel 768x486 = 146 Mb/s + audiio
Rec 601 8 bit 704x480 ~= 166 Mb/s

Huffyuv codec reduces these ~ 1/2.7 or 0.37x

Is 28 Mb/s absolutely sufficient for VHS Capture?

[2Bdecided]

Is 28 Mb/s absolutely sufficient for VHS Capture?

Depends on the amount of noise on the VHS, what you intend to do with it, and how picky you are.

For externally TBC'd and DNR'd VHS, it's hard to imagine that any lossess due to DV would be relevant, or even detectable after subsequent encoding (for most people it's got to be MPEG-2 or H.264 at the end of the day to be watched). It's always possible you could do some extreme processing in AVIsynth to reveal the limitations of DV.

For really horrible noisy VHS, I can imagine that DV could visibly change the signal. Whether this matters depends on if/how you denoise it later. You certainly can't encode noisy VHS straight to MPEG-2 or H.264 at sensible bitrates without adding far more artefacts - and far more objectionable ones at that.

Cheers,
David.

[edDV]

In theory, DV far excedes VHS sampling needs. This may mean it is capturing too wide a bandwidth for noisy VHS. This would also be true for any other capture option unless you analog low pass filter before A/D.

VHS has 3MHz luma bandwidth and ~0.5 MHz for R-Y and B-Y.

DV samples luma at 13.5 Ms/s (6.75 MHz Nyquist) and Cb and Cr at 3.375 Ms/s (1.7 MHz Nyquist).

DV does apply 5x DCT compression which is affected by noise. Alternative is uncompressed capture.

[nharikrishna]

Thanks 2Bdecided, my S-VHS set does a good job at TBC'ing and DNR'ing. My VHS cassettes are not all that noisy. they are 'fine'.

Thanks for the excellent technical info edDV....I see you answered many of my other threads. My knowledge keeps getting better day by day through these forums.